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<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    <a name="line.17"></a>
<FONT color="green">018</FONT>    package org.apache.commons.math3.ode.events;<a name="line.18"></a>
<FONT color="green">019</FONT>    <a name="line.19"></a>
<FONT color="green">020</FONT>    import org.apache.commons.math3.analysis.UnivariateFunction;<a name="line.20"></a>
<FONT color="green">021</FONT>    import org.apache.commons.math3.analysis.solvers.AllowedSolution;<a name="line.21"></a>
<FONT color="green">022</FONT>    import org.apache.commons.math3.analysis.solvers.BracketedUnivariateSolver;<a name="line.22"></a>
<FONT color="green">023</FONT>    import org.apache.commons.math3.analysis.solvers.PegasusSolver;<a name="line.23"></a>
<FONT color="green">024</FONT>    import org.apache.commons.math3.analysis.solvers.UnivariateSolver;<a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.commons.math3.analysis.solvers.UnivariateSolverUtils;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.commons.math3.exception.MaxCountExceededException;<a name="line.26"></a>
<FONT color="green">027</FONT>    import org.apache.commons.math3.exception.NoBracketingException;<a name="line.27"></a>
<FONT color="green">028</FONT>    import org.apache.commons.math3.ode.sampling.StepInterpolator;<a name="line.28"></a>
<FONT color="green">029</FONT>    import org.apache.commons.math3.util.FastMath;<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>    /** This class handles the state for one {@link EventHandler<a name="line.31"></a>
<FONT color="green">032</FONT>     * event handler} during integration steps.<a name="line.32"></a>
<FONT color="green">033</FONT>     *<a name="line.33"></a>
<FONT color="green">034</FONT>     * &lt;p&gt;Each time the integrator proposes a step, the event handler<a name="line.34"></a>
<FONT color="green">035</FONT>     * switching function should be checked. This class handles the state<a name="line.35"></a>
<FONT color="green">036</FONT>     * of one handler during one integration step, with references to the<a name="line.36"></a>
<FONT color="green">037</FONT>     * state at the end of the preceding step. This information is used to<a name="line.37"></a>
<FONT color="green">038</FONT>     * decide if the handler should trigger an event or not during the<a name="line.38"></a>
<FONT color="green">039</FONT>     * proposed step.&lt;/p&gt;<a name="line.39"></a>
<FONT color="green">040</FONT>     *<a name="line.40"></a>
<FONT color="green">041</FONT>     * @version $Id: EventState.java 1416643 2012-12-03 19:37:14Z tn $<a name="line.41"></a>
<FONT color="green">042</FONT>     * @since 1.2<a name="line.42"></a>
<FONT color="green">043</FONT>     */<a name="line.43"></a>
<FONT color="green">044</FONT>    public class EventState {<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>        /** Event handler. */<a name="line.46"></a>
<FONT color="green">047</FONT>        private final EventHandler handler;<a name="line.47"></a>
<FONT color="green">048</FONT>    <a name="line.48"></a>
<FONT color="green">049</FONT>        /** Maximal time interval between events handler checks. */<a name="line.49"></a>
<FONT color="green">050</FONT>        private final double maxCheckInterval;<a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>        /** Convergence threshold for event localization. */<a name="line.52"></a>
<FONT color="green">053</FONT>        private final double convergence;<a name="line.53"></a>
<FONT color="green">054</FONT>    <a name="line.54"></a>
<FONT color="green">055</FONT>        /** Upper limit in the iteration count for event localization. */<a name="line.55"></a>
<FONT color="green">056</FONT>        private final int maxIterationCount;<a name="line.56"></a>
<FONT color="green">057</FONT>    <a name="line.57"></a>
<FONT color="green">058</FONT>        /** Time at the beginning of the step. */<a name="line.58"></a>
<FONT color="green">059</FONT>        private double t0;<a name="line.59"></a>
<FONT color="green">060</FONT>    <a name="line.60"></a>
<FONT color="green">061</FONT>        /** Value of the events handler at the beginning of the step. */<a name="line.61"></a>
<FONT color="green">062</FONT>        private double g0;<a name="line.62"></a>
<FONT color="green">063</FONT>    <a name="line.63"></a>
<FONT color="green">064</FONT>        /** Simulated sign of g0 (we cheat when crossing events). */<a name="line.64"></a>
<FONT color="green">065</FONT>        private boolean g0Positive;<a name="line.65"></a>
<FONT color="green">066</FONT>    <a name="line.66"></a>
<FONT color="green">067</FONT>        /** Indicator of event expected during the step. */<a name="line.67"></a>
<FONT color="green">068</FONT>        private boolean pendingEvent;<a name="line.68"></a>
<FONT color="green">069</FONT>    <a name="line.69"></a>
<FONT color="green">070</FONT>        /** Occurrence time of the pending event. */<a name="line.70"></a>
<FONT color="green">071</FONT>        private double pendingEventTime;<a name="line.71"></a>
<FONT color="green">072</FONT>    <a name="line.72"></a>
<FONT color="green">073</FONT>        /** Occurrence time of the previous event. */<a name="line.73"></a>
<FONT color="green">074</FONT>        private double previousEventTime;<a name="line.74"></a>
<FONT color="green">075</FONT>    <a name="line.75"></a>
<FONT color="green">076</FONT>        /** Integration direction. */<a name="line.76"></a>
<FONT color="green">077</FONT>        private boolean forward;<a name="line.77"></a>
<FONT color="green">078</FONT>    <a name="line.78"></a>
<FONT color="green">079</FONT>        /** Variation direction around pending event.<a name="line.79"></a>
<FONT color="green">080</FONT>         *  (this is considered with respect to the integration direction)<a name="line.80"></a>
<FONT color="green">081</FONT>         */<a name="line.81"></a>
<FONT color="green">082</FONT>        private boolean increasing;<a name="line.82"></a>
<FONT color="green">083</FONT>    <a name="line.83"></a>
<FONT color="green">084</FONT>        /** Next action indicator. */<a name="line.84"></a>
<FONT color="green">085</FONT>        private EventHandler.Action nextAction;<a name="line.85"></a>
<FONT color="green">086</FONT>    <a name="line.86"></a>
<FONT color="green">087</FONT>        /** Root-finding algorithm to use to detect state events. */<a name="line.87"></a>
<FONT color="green">088</FONT>        private final UnivariateSolver solver;<a name="line.88"></a>
<FONT color="green">089</FONT>    <a name="line.89"></a>
<FONT color="green">090</FONT>        /** Simple constructor.<a name="line.90"></a>
<FONT color="green">091</FONT>         * @param handler event handler<a name="line.91"></a>
<FONT color="green">092</FONT>         * @param maxCheckInterval maximal time interval between switching<a name="line.92"></a>
<FONT color="green">093</FONT>         * function checks (this interval prevents missing sign changes in<a name="line.93"></a>
<FONT color="green">094</FONT>         * case the integration steps becomes very large)<a name="line.94"></a>
<FONT color="green">095</FONT>         * @param convergence convergence threshold in the event time search<a name="line.95"></a>
<FONT color="green">096</FONT>         * @param maxIterationCount upper limit of the iteration count in<a name="line.96"></a>
<FONT color="green">097</FONT>         * the event time search<a name="line.97"></a>
<FONT color="green">098</FONT>         * @param solver Root-finding algorithm to use to detect state events<a name="line.98"></a>
<FONT color="green">099</FONT>         */<a name="line.99"></a>
<FONT color="green">100</FONT>        public EventState(final EventHandler handler, final double maxCheckInterval,<a name="line.100"></a>
<FONT color="green">101</FONT>                          final double convergence, final int maxIterationCount,<a name="line.101"></a>
<FONT color="green">102</FONT>                          final UnivariateSolver solver) {<a name="line.102"></a>
<FONT color="green">103</FONT>            this.handler           = handler;<a name="line.103"></a>
<FONT color="green">104</FONT>            this.maxCheckInterval  = maxCheckInterval;<a name="line.104"></a>
<FONT color="green">105</FONT>            this.convergence       = FastMath.abs(convergence);<a name="line.105"></a>
<FONT color="green">106</FONT>            this.maxIterationCount = maxIterationCount;<a name="line.106"></a>
<FONT color="green">107</FONT>            this.solver            = solver;<a name="line.107"></a>
<FONT color="green">108</FONT>    <a name="line.108"></a>
<FONT color="green">109</FONT>            // some dummy values ...<a name="line.109"></a>
<FONT color="green">110</FONT>            t0                = Double.NaN;<a name="line.110"></a>
<FONT color="green">111</FONT>            g0                = Double.NaN;<a name="line.111"></a>
<FONT color="green">112</FONT>            g0Positive        = true;<a name="line.112"></a>
<FONT color="green">113</FONT>            pendingEvent      = false;<a name="line.113"></a>
<FONT color="green">114</FONT>            pendingEventTime  = Double.NaN;<a name="line.114"></a>
<FONT color="green">115</FONT>            previousEventTime = Double.NaN;<a name="line.115"></a>
<FONT color="green">116</FONT>            increasing        = true;<a name="line.116"></a>
<FONT color="green">117</FONT>            nextAction        = EventHandler.Action.CONTINUE;<a name="line.117"></a>
<FONT color="green">118</FONT>    <a name="line.118"></a>
<FONT color="green">119</FONT>        }<a name="line.119"></a>
<FONT color="green">120</FONT>    <a name="line.120"></a>
<FONT color="green">121</FONT>        /** Get the underlying event handler.<a name="line.121"></a>
<FONT color="green">122</FONT>         * @return underlying event handler<a name="line.122"></a>
<FONT color="green">123</FONT>         */<a name="line.123"></a>
<FONT color="green">124</FONT>        public EventHandler getEventHandler() {<a name="line.124"></a>
<FONT color="green">125</FONT>            return handler;<a name="line.125"></a>
<FONT color="green">126</FONT>        }<a name="line.126"></a>
<FONT color="green">127</FONT>    <a name="line.127"></a>
<FONT color="green">128</FONT>        /** Get the maximal time interval between events handler checks.<a name="line.128"></a>
<FONT color="green">129</FONT>         * @return maximal time interval between events handler checks<a name="line.129"></a>
<FONT color="green">130</FONT>         */<a name="line.130"></a>
<FONT color="green">131</FONT>        public double getMaxCheckInterval() {<a name="line.131"></a>
<FONT color="green">132</FONT>            return maxCheckInterval;<a name="line.132"></a>
<FONT color="green">133</FONT>        }<a name="line.133"></a>
<FONT color="green">134</FONT>    <a name="line.134"></a>
<FONT color="green">135</FONT>        /** Get the convergence threshold for event localization.<a name="line.135"></a>
<FONT color="green">136</FONT>         * @return convergence threshold for event localization<a name="line.136"></a>
<FONT color="green">137</FONT>         */<a name="line.137"></a>
<FONT color="green">138</FONT>        public double getConvergence() {<a name="line.138"></a>
<FONT color="green">139</FONT>            return convergence;<a name="line.139"></a>
<FONT color="green">140</FONT>        }<a name="line.140"></a>
<FONT color="green">141</FONT>    <a name="line.141"></a>
<FONT color="green">142</FONT>        /** Get the upper limit in the iteration count for event localization.<a name="line.142"></a>
<FONT color="green">143</FONT>         * @return upper limit in the iteration count for event localization<a name="line.143"></a>
<FONT color="green">144</FONT>         */<a name="line.144"></a>
<FONT color="green">145</FONT>        public int getMaxIterationCount() {<a name="line.145"></a>
<FONT color="green">146</FONT>            return maxIterationCount;<a name="line.146"></a>
<FONT color="green">147</FONT>        }<a name="line.147"></a>
<FONT color="green">148</FONT>    <a name="line.148"></a>
<FONT color="green">149</FONT>        /** Reinitialize the beginning of the step.<a name="line.149"></a>
<FONT color="green">150</FONT>         * @param interpolator valid for the current step<a name="line.150"></a>
<FONT color="green">151</FONT>         * @exception MaxCountExceededException if the interpolator throws one because<a name="line.151"></a>
<FONT color="green">152</FONT>         * the number of functions evaluations is exceeded<a name="line.152"></a>
<FONT color="green">153</FONT>         */<a name="line.153"></a>
<FONT color="green">154</FONT>        public void reinitializeBegin(final StepInterpolator interpolator)<a name="line.154"></a>
<FONT color="green">155</FONT>            throws MaxCountExceededException {<a name="line.155"></a>
<FONT color="green">156</FONT>    <a name="line.156"></a>
<FONT color="green">157</FONT>            t0 = interpolator.getPreviousTime();<a name="line.157"></a>
<FONT color="green">158</FONT>            interpolator.setInterpolatedTime(t0);<a name="line.158"></a>
<FONT color="green">159</FONT>            g0 = handler.g(t0, interpolator.getInterpolatedState());<a name="line.159"></a>
<FONT color="green">160</FONT>            if (g0 == 0) {<a name="line.160"></a>
<FONT color="green">161</FONT>                // excerpt from MATH-421 issue:<a name="line.161"></a>
<FONT color="green">162</FONT>                // If an ODE solver is setup with an EventHandler that return STOP<a name="line.162"></a>
<FONT color="green">163</FONT>                // when the even is triggered, the integrator stops (which is exactly<a name="line.163"></a>
<FONT color="green">164</FONT>                // the expected behavior). If however the user wants to restart the<a name="line.164"></a>
<FONT color="green">165</FONT>                // solver from the final state reached at the event with the same<a name="line.165"></a>
<FONT color="green">166</FONT>                // configuration (expecting the event to be triggered again at a<a name="line.166"></a>
<FONT color="green">167</FONT>                // later time), then the integrator may fail to start. It can get stuck<a name="line.167"></a>
<FONT color="green">168</FONT>                // at the previous event. The use case for the bug MATH-421 is fairly<a name="line.168"></a>
<FONT color="green">169</FONT>                // general, so events occurring exactly at start in the first step should<a name="line.169"></a>
<FONT color="green">170</FONT>                // be ignored.<a name="line.170"></a>
<FONT color="green">171</FONT>    <a name="line.171"></a>
<FONT color="green">172</FONT>                // extremely rare case: there is a zero EXACTLY at interval start<a name="line.172"></a>
<FONT color="green">173</FONT>                // we will use the sign slightly after step beginning to force ignoring this zero<a name="line.173"></a>
<FONT color="green">174</FONT>                final double epsilon = FastMath.max(solver.getAbsoluteAccuracy(),<a name="line.174"></a>
<FONT color="green">175</FONT>                                                    FastMath.abs(solver.getRelativeAccuracy() * t0));<a name="line.175"></a>
<FONT color="green">176</FONT>                final double tStart = t0 + 0.5 * epsilon;<a name="line.176"></a>
<FONT color="green">177</FONT>                interpolator.setInterpolatedTime(tStart);<a name="line.177"></a>
<FONT color="green">178</FONT>                g0 = handler.g(tStart, interpolator.getInterpolatedState());<a name="line.178"></a>
<FONT color="green">179</FONT>            }<a name="line.179"></a>
<FONT color="green">180</FONT>            g0Positive = g0 &gt;= 0;<a name="line.180"></a>
<FONT color="green">181</FONT>    <a name="line.181"></a>
<FONT color="green">182</FONT>        }<a name="line.182"></a>
<FONT color="green">183</FONT>    <a name="line.183"></a>
<FONT color="green">184</FONT>        /** Evaluate the impact of the proposed step on the event handler.<a name="line.184"></a>
<FONT color="green">185</FONT>         * @param interpolator step interpolator for the proposed step<a name="line.185"></a>
<FONT color="green">186</FONT>         * @return true if the event handler triggers an event before<a name="line.186"></a>
<FONT color="green">187</FONT>         * the end of the proposed step<a name="line.187"></a>
<FONT color="green">188</FONT>         * @exception MaxCountExceededException if the interpolator throws one because<a name="line.188"></a>
<FONT color="green">189</FONT>         * the number of functions evaluations is exceeded<a name="line.189"></a>
<FONT color="green">190</FONT>         * @exception NoBracketingException if the event cannot be bracketed<a name="line.190"></a>
<FONT color="green">191</FONT>         */<a name="line.191"></a>
<FONT color="green">192</FONT>        public boolean evaluateStep(final StepInterpolator interpolator)<a name="line.192"></a>
<FONT color="green">193</FONT>            throws MaxCountExceededException, NoBracketingException {<a name="line.193"></a>
<FONT color="green">194</FONT>    <a name="line.194"></a>
<FONT color="green">195</FONT>            try {<a name="line.195"></a>
<FONT color="green">196</FONT>                forward = interpolator.isForward();<a name="line.196"></a>
<FONT color="green">197</FONT>                final double t1 = interpolator.getCurrentTime();<a name="line.197"></a>
<FONT color="green">198</FONT>                final double dt = t1 - t0;<a name="line.198"></a>
<FONT color="green">199</FONT>                if (FastMath.abs(dt) &lt; convergence) {<a name="line.199"></a>
<FONT color="green">200</FONT>                    // we cannot do anything on such a small step, don't trigger any events<a name="line.200"></a>
<FONT color="green">201</FONT>                    return false;<a name="line.201"></a>
<FONT color="green">202</FONT>                }<a name="line.202"></a>
<FONT color="green">203</FONT>                final int    n = FastMath.max(1, (int) FastMath.ceil(FastMath.abs(dt) / maxCheckInterval));<a name="line.203"></a>
<FONT color="green">204</FONT>                final double h = dt / n;<a name="line.204"></a>
<FONT color="green">205</FONT>    <a name="line.205"></a>
<FONT color="green">206</FONT>                final UnivariateFunction f = new UnivariateFunction() {<a name="line.206"></a>
<FONT color="green">207</FONT>                    public double value(final double t) throws LocalMaxCountExceededException {<a name="line.207"></a>
<FONT color="green">208</FONT>                        try {<a name="line.208"></a>
<FONT color="green">209</FONT>                            interpolator.setInterpolatedTime(t);<a name="line.209"></a>
<FONT color="green">210</FONT>                            return handler.g(t, interpolator.getInterpolatedState());<a name="line.210"></a>
<FONT color="green">211</FONT>                        } catch (MaxCountExceededException mcee) {<a name="line.211"></a>
<FONT color="green">212</FONT>                            throw new LocalMaxCountExceededException(mcee);<a name="line.212"></a>
<FONT color="green">213</FONT>                        }<a name="line.213"></a>
<FONT color="green">214</FONT>                    }<a name="line.214"></a>
<FONT color="green">215</FONT>                };<a name="line.215"></a>
<FONT color="green">216</FONT>    <a name="line.216"></a>
<FONT color="green">217</FONT>                double ta = t0;<a name="line.217"></a>
<FONT color="green">218</FONT>                double ga = g0;<a name="line.218"></a>
<FONT color="green">219</FONT>                for (int i = 0; i &lt; n; ++i) {<a name="line.219"></a>
<FONT color="green">220</FONT>    <a name="line.220"></a>
<FONT color="green">221</FONT>                    // evaluate handler value at the end of the substep<a name="line.221"></a>
<FONT color="green">222</FONT>                    final double tb = t0 + (i + 1) * h;<a name="line.222"></a>
<FONT color="green">223</FONT>                    interpolator.setInterpolatedTime(tb);<a name="line.223"></a>
<FONT color="green">224</FONT>                    final double gb = handler.g(tb, interpolator.getInterpolatedState());<a name="line.224"></a>
<FONT color="green">225</FONT>    <a name="line.225"></a>
<FONT color="green">226</FONT>                    // check events occurrence<a name="line.226"></a>
<FONT color="green">227</FONT>                    if (g0Positive ^ (gb &gt;= 0)) {<a name="line.227"></a>
<FONT color="green">228</FONT>                        // there is a sign change: an event is expected during this step<a name="line.228"></a>
<FONT color="green">229</FONT>    <a name="line.229"></a>
<FONT color="green">230</FONT>                        // variation direction, with respect to the integration direction<a name="line.230"></a>
<FONT color="green">231</FONT>                        increasing = gb &gt;= ga;<a name="line.231"></a>
<FONT color="green">232</FONT>    <a name="line.232"></a>
<FONT color="green">233</FONT>                        // find the event time making sure we select a solution just at or past the exact root<a name="line.233"></a>
<FONT color="green">234</FONT>                        final double root;<a name="line.234"></a>
<FONT color="green">235</FONT>                        if (solver instanceof BracketedUnivariateSolver&lt;?&gt;) {<a name="line.235"></a>
<FONT color="green">236</FONT>                            @SuppressWarnings("unchecked")<a name="line.236"></a>
<FONT color="green">237</FONT>                            BracketedUnivariateSolver&lt;UnivariateFunction&gt; bracketing =<a name="line.237"></a>
<FONT color="green">238</FONT>                                    (BracketedUnivariateSolver&lt;UnivariateFunction&gt;) solver;<a name="line.238"></a>
<FONT color="green">239</FONT>                            root = forward ?<a name="line.239"></a>
<FONT color="green">240</FONT>                                   bracketing.solve(maxIterationCount, f, ta, tb, AllowedSolution.RIGHT_SIDE) :<a name="line.240"></a>
<FONT color="green">241</FONT>                                   bracketing.solve(maxIterationCount, f, tb, ta, AllowedSolution.LEFT_SIDE);<a name="line.241"></a>
<FONT color="green">242</FONT>                        } else {<a name="line.242"></a>
<FONT color="green">243</FONT>                            final double baseRoot = forward ?<a name="line.243"></a>
<FONT color="green">244</FONT>                                                    solver.solve(maxIterationCount, f, ta, tb) :<a name="line.244"></a>
<FONT color="green">245</FONT>                                                    solver.solve(maxIterationCount, f, tb, ta);<a name="line.245"></a>
<FONT color="green">246</FONT>                            final int remainingEval = maxIterationCount - solver.getEvaluations();<a name="line.246"></a>
<FONT color="green">247</FONT>                            BracketedUnivariateSolver&lt;UnivariateFunction&gt; bracketing =<a name="line.247"></a>
<FONT color="green">248</FONT>                                    new PegasusSolver(solver.getRelativeAccuracy(), solver.getAbsoluteAccuracy());<a name="line.248"></a>
<FONT color="green">249</FONT>                            root = forward ?<a name="line.249"></a>
<FONT color="green">250</FONT>                                   UnivariateSolverUtils.forceSide(remainingEval, f, bracketing,<a name="line.250"></a>
<FONT color="green">251</FONT>                                                                       baseRoot, ta, tb, AllowedSolution.RIGHT_SIDE) :<a name="line.251"></a>
<FONT color="green">252</FONT>                                   UnivariateSolverUtils.forceSide(remainingEval, f, bracketing,<a name="line.252"></a>
<FONT color="green">253</FONT>                                                                       baseRoot, tb, ta, AllowedSolution.LEFT_SIDE);<a name="line.253"></a>
<FONT color="green">254</FONT>                        }<a name="line.254"></a>
<FONT color="green">255</FONT>    <a name="line.255"></a>
<FONT color="green">256</FONT>                        if ((!Double.isNaN(previousEventTime)) &amp;&amp;<a name="line.256"></a>
<FONT color="green">257</FONT>                            (FastMath.abs(root - ta) &lt;= convergence) &amp;&amp;<a name="line.257"></a>
<FONT color="green">258</FONT>                            (FastMath.abs(root - previousEventTime) &lt;= convergence)) {<a name="line.258"></a>
<FONT color="green">259</FONT>                            // we have either found nothing or found (again ?) a past event,<a name="line.259"></a>
<FONT color="green">260</FONT>                            // retry the substep excluding this value<a name="line.260"></a>
<FONT color="green">261</FONT>                            ta = forward ? ta + convergence : ta - convergence;<a name="line.261"></a>
<FONT color="green">262</FONT>                            ga = f.value(ta);<a name="line.262"></a>
<FONT color="green">263</FONT>                            --i;<a name="line.263"></a>
<FONT color="green">264</FONT>                        } else if (Double.isNaN(previousEventTime) ||<a name="line.264"></a>
<FONT color="green">265</FONT>                                   (FastMath.abs(previousEventTime - root) &gt; convergence)) {<a name="line.265"></a>
<FONT color="green">266</FONT>                            pendingEventTime = root;<a name="line.266"></a>
<FONT color="green">267</FONT>                            pendingEvent = true;<a name="line.267"></a>
<FONT color="green">268</FONT>                            return true;<a name="line.268"></a>
<FONT color="green">269</FONT>                        } else {<a name="line.269"></a>
<FONT color="green">270</FONT>                            // no sign change: there is no event for now<a name="line.270"></a>
<FONT color="green">271</FONT>                            ta = tb;<a name="line.271"></a>
<FONT color="green">272</FONT>                            ga = gb;<a name="line.272"></a>
<FONT color="green">273</FONT>                        }<a name="line.273"></a>
<FONT color="green">274</FONT>    <a name="line.274"></a>
<FONT color="green">275</FONT>                    } else {<a name="line.275"></a>
<FONT color="green">276</FONT>                        // no sign change: there is no event for now<a name="line.276"></a>
<FONT color="green">277</FONT>                        ta = tb;<a name="line.277"></a>
<FONT color="green">278</FONT>                        ga = gb;<a name="line.278"></a>
<FONT color="green">279</FONT>                    }<a name="line.279"></a>
<FONT color="green">280</FONT>    <a name="line.280"></a>
<FONT color="green">281</FONT>                }<a name="line.281"></a>
<FONT color="green">282</FONT>    <a name="line.282"></a>
<FONT color="green">283</FONT>                // no event during the whole step<a name="line.283"></a>
<FONT color="green">284</FONT>                pendingEvent     = false;<a name="line.284"></a>
<FONT color="green">285</FONT>                pendingEventTime = Double.NaN;<a name="line.285"></a>
<FONT color="green">286</FONT>                return false;<a name="line.286"></a>
<FONT color="green">287</FONT>    <a name="line.287"></a>
<FONT color="green">288</FONT>            } catch (LocalMaxCountExceededException lmcee) {<a name="line.288"></a>
<FONT color="green">289</FONT>                throw lmcee.getException();<a name="line.289"></a>
<FONT color="green">290</FONT>            }<a name="line.290"></a>
<FONT color="green">291</FONT>    <a name="line.291"></a>
<FONT color="green">292</FONT>        }<a name="line.292"></a>
<FONT color="green">293</FONT>    <a name="line.293"></a>
<FONT color="green">294</FONT>        /** Get the occurrence time of the event triggered in the current step.<a name="line.294"></a>
<FONT color="green">295</FONT>         * @return occurrence time of the event triggered in the current<a name="line.295"></a>
<FONT color="green">296</FONT>         * step or infinity if no events are triggered<a name="line.296"></a>
<FONT color="green">297</FONT>         */<a name="line.297"></a>
<FONT color="green">298</FONT>        public double getEventTime() {<a name="line.298"></a>
<FONT color="green">299</FONT>            return pendingEvent ?<a name="line.299"></a>
<FONT color="green">300</FONT>                   pendingEventTime :<a name="line.300"></a>
<FONT color="green">301</FONT>                   (forward ? Double.POSITIVE_INFINITY : Double.NEGATIVE_INFINITY);<a name="line.301"></a>
<FONT color="green">302</FONT>        }<a name="line.302"></a>
<FONT color="green">303</FONT>    <a name="line.303"></a>
<FONT color="green">304</FONT>        /** Acknowledge the fact the step has been accepted by the integrator.<a name="line.304"></a>
<FONT color="green">305</FONT>         * @param t value of the independent &lt;i&gt;time&lt;/i&gt; variable at the<a name="line.305"></a>
<FONT color="green">306</FONT>         * end of the step<a name="line.306"></a>
<FONT color="green">307</FONT>         * @param y array containing the current value of the state vector<a name="line.307"></a>
<FONT color="green">308</FONT>         * at the end of the step<a name="line.308"></a>
<FONT color="green">309</FONT>         */<a name="line.309"></a>
<FONT color="green">310</FONT>        public void stepAccepted(final double t, final double[] y) {<a name="line.310"></a>
<FONT color="green">311</FONT>    <a name="line.311"></a>
<FONT color="green">312</FONT>            t0 = t;<a name="line.312"></a>
<FONT color="green">313</FONT>            g0 = handler.g(t, y);<a name="line.313"></a>
<FONT color="green">314</FONT>    <a name="line.314"></a>
<FONT color="green">315</FONT>            if (pendingEvent &amp;&amp; (FastMath.abs(pendingEventTime - t) &lt;= convergence)) {<a name="line.315"></a>
<FONT color="green">316</FONT>                // force the sign to its value "just after the event"<a name="line.316"></a>
<FONT color="green">317</FONT>                previousEventTime = t;<a name="line.317"></a>
<FONT color="green">318</FONT>                g0Positive        = increasing;<a name="line.318"></a>
<FONT color="green">319</FONT>                nextAction        = handler.eventOccurred(t, y, !(increasing ^ forward));<a name="line.319"></a>
<FONT color="green">320</FONT>            } else {<a name="line.320"></a>
<FONT color="green">321</FONT>                g0Positive = g0 &gt;= 0;<a name="line.321"></a>
<FONT color="green">322</FONT>                nextAction = EventHandler.Action.CONTINUE;<a name="line.322"></a>
<FONT color="green">323</FONT>            }<a name="line.323"></a>
<FONT color="green">324</FONT>        }<a name="line.324"></a>
<FONT color="green">325</FONT>    <a name="line.325"></a>
<FONT color="green">326</FONT>        /** Check if the integration should be stopped at the end of the<a name="line.326"></a>
<FONT color="green">327</FONT>         * current step.<a name="line.327"></a>
<FONT color="green">328</FONT>         * @return true if the integration should be stopped<a name="line.328"></a>
<FONT color="green">329</FONT>         */<a name="line.329"></a>
<FONT color="green">330</FONT>        public boolean stop() {<a name="line.330"></a>
<FONT color="green">331</FONT>            return nextAction == EventHandler.Action.STOP;<a name="line.331"></a>
<FONT color="green">332</FONT>        }<a name="line.332"></a>
<FONT color="green">333</FONT>    <a name="line.333"></a>
<FONT color="green">334</FONT>        /** Let the event handler reset the state if it wants.<a name="line.334"></a>
<FONT color="green">335</FONT>         * @param t value of the independent &lt;i&gt;time&lt;/i&gt; variable at the<a name="line.335"></a>
<FONT color="green">336</FONT>         * beginning of the next step<a name="line.336"></a>
<FONT color="green">337</FONT>         * @param y array were to put the desired state vector at the beginning<a name="line.337"></a>
<FONT color="green">338</FONT>         * of the next step<a name="line.338"></a>
<FONT color="green">339</FONT>         * @return true if the integrator should reset the derivatives too<a name="line.339"></a>
<FONT color="green">340</FONT>         */<a name="line.340"></a>
<FONT color="green">341</FONT>        public boolean reset(final double t, final double[] y) {<a name="line.341"></a>
<FONT color="green">342</FONT>    <a name="line.342"></a>
<FONT color="green">343</FONT>            if (!(pendingEvent &amp;&amp; (FastMath.abs(pendingEventTime - t) &lt;= convergence))) {<a name="line.343"></a>
<FONT color="green">344</FONT>                return false;<a name="line.344"></a>
<FONT color="green">345</FONT>            }<a name="line.345"></a>
<FONT color="green">346</FONT>    <a name="line.346"></a>
<FONT color="green">347</FONT>            if (nextAction == EventHandler.Action.RESET_STATE) {<a name="line.347"></a>
<FONT color="green">348</FONT>                handler.resetState(t, y);<a name="line.348"></a>
<FONT color="green">349</FONT>            }<a name="line.349"></a>
<FONT color="green">350</FONT>            pendingEvent      = false;<a name="line.350"></a>
<FONT color="green">351</FONT>            pendingEventTime  = Double.NaN;<a name="line.351"></a>
<FONT color="green">352</FONT>    <a name="line.352"></a>
<FONT color="green">353</FONT>            return (nextAction == EventHandler.Action.RESET_STATE) ||<a name="line.353"></a>
<FONT color="green">354</FONT>                   (nextAction == EventHandler.Action.RESET_DERIVATIVES);<a name="line.354"></a>
<FONT color="green">355</FONT>    <a name="line.355"></a>
<FONT color="green">356</FONT>        }<a name="line.356"></a>
<FONT color="green">357</FONT>    <a name="line.357"></a>
<FONT color="green">358</FONT>        /** Local wrapper to propagate exceptions. */<a name="line.358"></a>
<FONT color="green">359</FONT>        private static class LocalMaxCountExceededException extends RuntimeException {<a name="line.359"></a>
<FONT color="green">360</FONT>    <a name="line.360"></a>
<FONT color="green">361</FONT>            /** Serializable UID. */<a name="line.361"></a>
<FONT color="green">362</FONT>            private static final long serialVersionUID = 20120901L;<a name="line.362"></a>
<FONT color="green">363</FONT>    <a name="line.363"></a>
<FONT color="green">364</FONT>            /** Wrapped exception. */<a name="line.364"></a>
<FONT color="green">365</FONT>            private final MaxCountExceededException wrapped;<a name="line.365"></a>
<FONT color="green">366</FONT>    <a name="line.366"></a>
<FONT color="green">367</FONT>            /** Simple constructor.<a name="line.367"></a>
<FONT color="green">368</FONT>             * @param exception exception to wrap<a name="line.368"></a>
<FONT color="green">369</FONT>             */<a name="line.369"></a>
<FONT color="green">370</FONT>            public LocalMaxCountExceededException(final MaxCountExceededException exception) {<a name="line.370"></a>
<FONT color="green">371</FONT>                wrapped = exception;<a name="line.371"></a>
<FONT color="green">372</FONT>            }<a name="line.372"></a>
<FONT color="green">373</FONT>    <a name="line.373"></a>
<FONT color="green">374</FONT>            /** Get the wrapped exception.<a name="line.374"></a>
<FONT color="green">375</FONT>             * @return wrapped exception<a name="line.375"></a>
<FONT color="green">376</FONT>             */<a name="line.376"></a>
<FONT color="green">377</FONT>            public MaxCountExceededException getException() {<a name="line.377"></a>
<FONT color="green">378</FONT>                return wrapped;<a name="line.378"></a>
<FONT color="green">379</FONT>            }<a name="line.379"></a>
<FONT color="green">380</FONT>    <a name="line.380"></a>
<FONT color="green">381</FONT>        }<a name="line.381"></a>
<FONT color="green">382</FONT>    <a name="line.382"></a>
<FONT color="green">383</FONT>    }<a name="line.383"></a>




























































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